What is meant by "ground return" in the context of takeoff performance?

The term "ground return" refers to the recovery of lift due to ground effect. Ground effect occurs when an aircraft is in close proximity to the ground, typically within a distance of about one wingspan. As the aircraft nears the ground during takeoff, the airflow around the wings is affected by the ground’s presence, causing increased lift and reduced induced drag. This phenomenon allows the aircraft to achieve more lift at lower speeds, which is particularly beneficial during the takeoff roll.

This effect enhances the aircraft's performance right near the ground, allowing it to lift off with greater efficiency and at a lower speed compared to flying at altitude, where no ground effect is present. Thus, acknowledging ground effect as "ground return" provides significant insight into how aircraft can optimize their takeoff performance under certain conditions. Understanding this concept is crucial for pilots as it influences the required takeoff distance and the aircraft's handling characteristics close to the runway surface.